The Object of your Desire
Ajax aficionados often find themselves with heaps of Json data, often arrays of data, fresh from the server, which they then magic into Html client-side.
A number of options exist for searching for a specific item in an array:
- jQuery.inArray(value,array) of jQuery
- Array.indexOf(array,item, start) of MS Ajax
But what if you have an array of objects?
You can use JavaScript’s built-in indexOf(obj) method for arrays to compare for object identity:
arr.indexOf(obj);
But this requires the entire hotly-sought object and, apparently, this may not work in some browsers, such as IE6, without a creative work-around.
A Generic (and Perhaps Obvious) Solution
Recently, I wrote the following function:
function ArrayIndexOf(a, fnc) {
if (!fnc || typeof (fnc) != 'function') {
return -1;
}
if (!a || !a.length || a.length < 1) return -1;
for (var i = 0; i < a.length; i++) {
if (fnc(a[i])) return i;
}
return -1;
}ArrayIndexOf(a, fnc) takes two parameters:
- the array
- a function of signature: bool f(item) {}
ArrayIndexOf compares each array item with, well, whatever you want, and returns the index of the item in the array, or -1 if there is no match. This approach gives you the flexibility to search for whatever specific field, or fields, you desire.
Sample usage:
var i = ArrayIndexOf(arrMovies, function(obj) {
return obj.MovieTitle == 'The Matrix';
});
if (-1 != i) {
alert('Found it! (Psst: take the blue pill!)');
}Disclaimer:
- I haven’t tested this code for performance, so if your arrays are immense, test it out
- Handle with care. JavaScript’s type-insensitivity means you better be sure the object properties you test against exist if you don’t want to crash and burn.
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